1. Field of the Disclosure
Embodiments generally relate to input sensing and, in particular, to capacitive input sensing in the presence of a uniform conductor.
2. Description of the Related Art
Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location, and/or motion of one or more input objects. Input objects can be at or near the surface of the proximity sensor device (“touch sensing”) or hovering over the surface of the proximity sensor device (“proximity sensing” or “hover sensing”). Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems (such as touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (such as touch screens integrated in cellular phones or tablet computers).
Proximity sensor devices that employ changes in capacitance to sense input object(s) can be detrimentally affected when the input object(s) are in the presence of a uniform conductor. For example, if a capacitive sensing device is submerged in water, the water, a uniform conductor, saturates the device. When the device is saturated, changes in capacitance caused by the input object(s) are difficult if not impossible to detect.